客户端javascript从异步调用解包的值

function fetchData(callback) {
  // 异步操作获取数据
  setTimeout(() => {
    const data = 'Hello, World!';
    callback(data); // 调用回调函数处理解包的值
  }, 1000);
}

fetchData((data) => {
  console.log(data); // 处理解包的值
});

function fetchData() {
  return new Promise((resolve, reject) => {
    // 异步操作获取数据
    setTimeout(() => {
      const data = 'Hello, World!';
      resolve(data); // 解包的值通过resolve方法传递
    }, 1000);
  });
}

fetchData().then((data) => {
  console.log(data); // 处理解包的值
});

async function fetchData() {
  return new Promise((resolve, reject) => {
    // 异步操作获取数据
    setTimeout(() => {
      const data = 'Hello, World!';
      resolve(data); // 解包的值通过resolve方法传递
    }, 1000);
  });
}

(async () => {
  const data = await fetchData(); // 等待异步调用解包的值
  console.log(data); // 处理解包的值
})();